The new research, published in the Journal of Sleep Research, sampled ten children - five girls and five boys, all aged three and four - who were denied their three-hour afternoon nap at pre-school, then kept awake for two hours beyond their normal bed-times.

During this sample day analysts found the youngsters consumed 20 per cent more calories, 25 per cent more sugar and 26 per cent more carbohydrates.

The following day, when the children were allowed their usual level of rest, they returned to their normal eating habits.

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Kids who don't sleep enough consumed 20 per cent more calories, 25 per cent more sugar and 26 per cent more carbohydrates

Professor Monique LeBourgeois, who lead the study, said: "We found that sleep loss increased the dietary intake of preschoolers on both the day of and the day after restricted sleep."

"These results may shed light on how sleep loss can increase weight gain and why a number of large studies show preschoolers who do not get enough sleep are more likely to be obese as a child and later in life."

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In 2014, 23 per cent of American children under the age of five years old were overweight or obese, said LeBourgeois. Meanwhile, here in the UK, one in three kids are obese or overweight by the age of 11.

"To our knowledge, this is the first published study to experimentally measure the effects of sleep loss on food consumption in preschool children," said Elsa Mullins, the study first author and a CU Boulder researcher who worked with LeBourgeois as an undergraduate.

"Our results are consistent with those from other studies of adults and adolescents, showing increased caloric intake on days that subjects were sleep deprived," she said.

PA:Press Association

The study found that children who fail to get enough rest are likely to become obese as adults